Brachmann-de Lange Syndrome (BDLS) consists of multiple congenital anomalies and mental retardation. The etiology is unknown. It is a clinical diagnosis and no useful laboratory test exists. Furthermore, there is a vexing clinical overlap with chromosome 3q duplication syndrome. New basic findings suggest that BDLS fibroblasts may have a measureable abnormality not previously noted in blood cells. This protocol intends to confirm this finding by analyzing blood cells and skin fibroblasts from twenty BDLS patients.